wrong_code stringlengths 3 123 | correct_code stringlengths 3 155 | explanation stringclasses 101
values | language stringclasses 26
values |
|---|---|---|---|
if a = 95: | if a == 95: | Use == for comparison. | Python |
raise 'info' | raise Exception('info') | Raise needs an exception class. | Python |
z = info | z = 'info' | Quote strings. | Python |
math.sqrt(16) | import math
math.sqrt(16) | Import module first. | Python |
{{"name":"value" "status":96}} | {{"name":"value", "status":96}} | Add comma. | JSON |
[20, 39, 9 | [20, 39, 9] | Close bracket. | Python |
class Person {{ int a; }}; | class Person {{ public: int a; }}; | Make public. | C++ |
console.log('output' | console.log('output') | Close parenthesis. | JavaScript |
void render();
int main(){{render();}} | void render(); // prototype
int main(){{render();}} | Declare before use. | C++ |
let result: i32 = "message"; | let result: &str = "message"; | Type mismatch. | Rust |
ArrayList list = new ArrayList(); | ArrayList<String> list = new ArrayList<>(); | Use generics. | Java |
<input type='text' value='test'> | <input type='text' value='test' name='id'> | Add name attribute. | HTML |
while read line; do echo $line; done < data.txt | while read line; do echo $line; done < data.txt | Correct. | Shell |
INSERT INTO users VALUES ('message',32) | INSERT INTO users (id, role) VALUES ('message',32); | Specify columns. | SQL |
if (b = 48) {} | if (b == 48) {} | Use ==. | Dart |
x = 5; if x > 3, disp('large'), end | x = 5; if x > 3, disp('large'), end | Correct. | MATLAB |
var x = 5; x = "hello" | var x = "hello" | Type mismatch. | Swift |
$values[89] = 5; | if (isset($values[89])) $values[89] = 5; | Check existence. | PHP |
<img src='world.jpg'> | <img src='world.jpg' alt='desc'> | Add alt text. | HTML |
{{'value':'result'}} | {{"value":"result"}} | Use double quotes. | JSON |
Order.save(); | Order.save().then(()=>{{}}).catch(err=>{{}}); | Handle promise. | Node.js |
let num = 64; | let num = 64; | Correct. | JavaScript |
SELECT COUNT(*) FROM orders | SELECT COUNT(*) FROM orders; | Missing semicolon. | SQL |
def baz():
print('output') | def baz():
print('output') | Indent function body. | Python |
list[80] | if (list.indices.contains(80)) list[80] | Check index. | Kotlin |
class = 'data' | class_name = 'data' | 'class' is a keyword. | Python |
while count > 98
count -= 1 | while count > 98:
count -= 1 | Colon missing after while. | Python |
#content {{ color: green; }} | #content {{ color: green; }} | Correct. | CSS |
list:
- item1
- item2 | list:
- item1
- item2 | Correct. | YAML |
lambda x: x+1 | lambda x: x+1 | Correct lambda. | Python |
if ($result = 43) {{}} | if ($result -eq 43) {{}} | Use -eq. | PowerShell |
bar | bar() | Add parentheses. | Kotlin |
let data = 'hello' | let data = "hello" | Double quotes. | Swift |
for i in $(ls); do echo $i; done | for i in $(ls); do echo $i; done | Correct. | Shell |
if (result) console.log('yes') else console.log('no') | if (result) console.log('yes'); else console.log('no'); | Missing semicolon. | JavaScript |
z > 17 & b < 35 | z > 17 and b < 35 | Use 'and' not '&'. | Python |
if result = 20 then
print('result')
end | if result == 20 then
print('result')
end | Use ==. | Lua |
int main() {{ return 0; }} | int main() {{ return 0; }} | Correct. | C++ |
if index > 14
puts 'world' | if index > 14
puts 'world'
end | Add 'end'. | Ruby |
items[10] | if items.indices.contains(10) {{ items[10] }} | Check index. | Swift |
h1 {{ font-size:2px color:#fff; }} | h1 {{ font-size:2px; color:#fff; }} | Add semicolon. | CSS |
x <- 5; if (x > 3) print('large') | x <- 5; if (x > 3) print('large') | Correct. | R |
arr.forEach(function(x) {{ console.log(x); }}) | arr.forEach((x) => {{ console.log(x); }}) | Arrow functions are cleaner. | JavaScript |
if count = 72 | if count == 72 | Use ==. | Ruby |
<center>message</center> | <div style='text-align:center;'>message</div> | Use CSS. | HTML |
print 'info' | print 'info'; | Add semicolon. | Perl |
else
print('message') | else:
print('message') | Colon after else. | Python |
<a href='https://test.org' target='_blank'> | <a href='https://test.org' target='_blank' rel='noopener'> | Add rel for security. | HTML |
val temp = 'value' | val temp = "value" | Double quotes. | Kotlin |
val z = 28; z = 17 | var z = 28; z = 17 | Use var for reassignment. | Scala |
fs.readFile('input.csv', (err,data) => {{ if(err) throw err; }}); | fs.readFile('input.csv', (err,data) => {{ if(err) {{ console.error(err); return; }} }}); | Better error handling. | Node.js |
if bar = 90 {{}} | if bar == 90 {{}} | Use ==. | Swift |
if item > 78
print('data') | if item > 78:
print('data') | Colon missing after if. | Python |
let list=vec![14,21,82]; let head=&list[0]; list.push(11); | let mut list=vec![14,21,82]; let head=list[0]; list.push(11); | Copy instead of reference. | Rust |
with open('log.txt') as f:
data = f.read() | with open('log.txt') as f:
data = f.read() | Correct. | Python |
def bar(num):
return num + 1 | def bar(num):
return num + 1 | Correct. | Python |
public static void main(String[] args) {{}} | public static void main(String[] args) {{}} | Correct. | Java |
switch(index){{ case 61: break; }} | switch(index){{ case 61: break; default: break; }} | Add default case. | Java |
fn foo() -> i32 {{ 58 }} | fn foo() -> i32 {{ 58 }} | Correct. | Rust |
const index = 54; index = 55; | let index = 54; index = 55; | Cannot reassign const. | JavaScript |
if [ $result = 78 ]; then | if [ "$result" = 78 ]; then | Quote variable. | Shell |
name: value
age: 18 | name: value
age: 18 | Correct. | YAML |
type MyType = string | number; let x: MyType = true; | type MyType = string | number; let x: MyType = 'hello'; | Type not in union. | TypeScript |
<br></br> | <br> | Self-closing. | HTML |
const obj:Person = {{name:'value'}}; | const obj:Person = {{name:'value', age:52}}; | Add missing property. | TypeScript |
void main() {{ print('data') }} | void main() {{ print('data'); }} | Add semicolon. | Dart |
function test(): void {{ return 73; }} | function test(): number {{ return 73; }} | Return type mismatch. | TypeScript |
["message", 1] | ["message", 1] | Correct. | JSON |
try:
x = 1 / 0
except
pass | try:
x = 1 / 0
except Exception:
pass | Specify exception type. | Python |
if (c = 55) | if (c == 55) | Use ==. | Scala |
age: message
id: test, | age: message
id: test | Remove comma. | YAML |
{{"age":"info",}} | {{"age":"info"}} | Remove trailing comma. | JSON |
DELETE FROM items WHERE email=69 | DELETE FROM items WHERE email=69; | Add semicolon. | SQL |
for z in range(42)
print(z) | for z in range(42):
print(z) | Colon after for. | Python |
int arr[75]; arr[75]=5; | int arr[75]; if(75<75){{}} else arr[75]=5; | Bounds check. | C++ |
if ($x = 39) | if ($x == 39) | Use ==. | Perl |
$b = 42; if ($b = 42) {{}} | $b = 42; if ($b == 42) {{}} | Use ==. | PHP |
List(74,62,34) | List(74,62,34) | Correct. | Scala |
int* obj = nullptr; *obj=5; | int* obj = new int; *obj=5; | Allocate memory. | C++ |
UPDATE users SET age='message' WHERE status=81 | UPDATE users SET age='message' WHERE status=81; | Add semicolon. | SQL |
var x = 78; | var x = 78; | Correct. | Dart |
class Item
def method
end
end | class Item
def method
end
end | Correct. | Ruby |
<root><child>text</child></root> | <root><child>text</child></root> | Correct. | XML |
local foo = 35 | local foo = 35 | Correct. | Lua |
echo result data | echo 'result data' | Quote to prevent splitting. | Shell |
$x = 5; if ($x -eq 5) { Write-Host 'yes' } | $x = 5; if ($x -eq 5) { Write-Host 'yes' } | Correct. | PowerShell |
let temp: number | null = null; temp.toFixed(34); | let temp: number | null = null; if(temp!==null) temp.toFixed(34); | Null check. | TypeScript |
let str = String::from("hello"); let ref=&str; str.push_str("!"); | let mut str = String::from("hello"); let ref=&str; println!("{{}}", ref); str.push_str("!"); | Cannot mutate while borrowed. | Rust |
'data' + 85 | 'data' + str(85) | Can't add int to string. | Python |
items[50] | if (length(items) >= 50) items[50] | Check length. | R |
<?php
// code
?> | <?php
// code
?> | Correct. | PHP |
function test(c:string){{return c;}} test(51); | function test(c:string){{return c;}} test('test'); | Pass correct type. | TypeScript |
$arr[96] | if ($arr.Count -gt 96) {{ $arr[96] }} | Check bounds. | PowerShell |
.Product {{ color: blue; }} | .Product {{ color: blue; }} | Correct. | CSS |
disp('hello') | disp('hello') | Correct. | MATLAB |
<ul><li>data<li>hello</ul> | <ul><li>data</li><li>hello</li></ul> | Close li. | HTML |
int &ref; | int x; int &ref = x; | Reference must be initialized. | C++ |
let bar = 80; bar += 1; | let mut bar = 80; bar += 1; | Need mut to modify. | Rust |
cin >> temp
cout << temp; | cin >> temp;
cout << temp; | Add semicolon. | C++ |
[x*x for x in values if x > 60] | [x*x for x in values if x > 60] | Correct list comprehension. | Python |
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